Fig. 1

a Distribution of Plasmodium knowlesi cases based on estimated date of first presentation of symptoms. Initials and case number of patients correspond with those in Table 1. 15 PCR confirmed Pk cases and two suspected Pk cases (SF and RV from Table 1) are mapped. Red cross: position of health facilities in Sabang including both Primary Health (PHC) and hospitals (RSUD and RSAL). Dotted red ellipse: cluster of cases at Iboih Village. Dotted purple ellipse: cluster of cases in a family at Ie Meulee Village. b Position of Sabang within Aceh Province. c Position of Sabang within the Indonesian archipelago and Malaysia